Bladder of mammals is under a dual control of autonomic nerve and detrusor relaxes via an adrenaline β receptor by stimulation of sympathetic nerve upon urination while, upon excretion of urine, it contracts via a muscarine receptor by stimulation of parasympathetic nerve. As a remedy for overactive bladder resulted when the dual control as such is unbalanced, anticholinergic agents such as propiverine hydrochloride and oxybutynin hydrochloride have been mostly used at present. However, there are intractable cases showing resistance to such compounds and there are side effects caused by anticholinergic agents such as urinary dysfunction and dry mouth and, therefore, it is the current status that satisfactory clinical results are not always achieved.
Further, as a result of increase in population of aged people in recent years, numbers of patients suffering from overactive bladder are increasing year by year and, in view of QOL (quality of life) of patients, there has been a brisk demand for the development of new drugs.
The present inventors reported in Example 41 of a pamphlet of International Laid-Open WO 99/20607 that (R)-2-(2-aminothiazol-4-yl)-4′-[2-[(2-hydroxy-2-phenylethyl)amino]-ethyl]acetic acid anilide dihydrochloride has both promotion action for insulin secretion and enhancing action for insulin sensitivity and further has anti-obese and anti-hyperlipemic actions whereby it is a useful compound for the treatment of diabetes mellitus but there is neither suggestion nor disclosure for the therapeutic use for overactive bladder (refer to Patent Document 1).

In the meanwhile, in a pamphlet of International Laid-Open WO 98/07445, as an agent for prevention and treatment of urinary frequency and urinary incontinence containing a drug having stimulating action to a β3-adrenaline receptor as an active ingredient, there is mentioned that CGP-12,177A represented by the following chemical structural formula has a relaxation action for bladder (refer to Patent Document 2). CGP-12,177A has been known as a selective drug having stimulating action to a β3-adrenaline receptor (refer to Non-Patent Documents 1 and 2).

In a pamphlet of International Laid-Open WO 99/31045, compounds represented by the following formula are mentioned as having a stimulating action to a β3-adrenaline receptor and as an agent for prevention or treatment of diseases caused by obesity, hyperglycemia and acceleration of movement of intestinal tract and diseases caused by urinary frequency or urinary incontinence, melancholia, biliary calculus or acceleration of bile duct movement (refer to Patent Document 3).

(In the formula, R1 is hydroxyl group, a lower alkyl group, an aralkoxy group, amino group, etc.; R2 is hydroxyl group or a lower alkyl group; R3 is hydrogen atom or halogen atom; R4 and R5 each is hydrogen atom, halogen atom or a lower alkyl group; and A is a lower alkylene group.)
In a pamphlet of International Laid-Open WO 99/52856, compounds represented by the following formula are mentioned as having a stimulating action to a β3-adrenaline receptor and as an agent for prevention or treatment of diseases caused by obesity, hyperglycemia and acceleration of movement of intestinal tract and diseases caused by urinary frequency or urinary incontinence, melancholia, biliary calculus or acceleration of bile duct movement (refer to Patent Document 4).

(In the formula, R1 is hydrogen atom, a lower alkyl group or an aralkyl group; R2 is hydrogen atom, a lower alkyl group or halogen atom; and A is oxygen atom or imino group.)
In a pamphlet of International Laid-Open WO 00/02846, compounds represented by the following formula are mentioned as having a stimulating action to a β3-adrenaline receptor and as an agent for prevention or treatment of diseases caused by obesity, hyperglycemia and acceleration of movement of intestinal tract and diseases caused by urinary frequency or urinary incontinence, melancholia, biliary calculus or acceleration of bile duct movement (refer to Patent Document 5).

(In the formula, R1 is hydroxyl group, etc.; one of R2 and R3 is hydrogen atom, halogen atom, etc. and another is hydrogen atom; and R4 is halogen atom, etc.)    Patent Document 1: Pamphlet of International Laid-Open WO 99/20607    Patent Document 2: Pamphlet of International Laid-Open WO 98/07445    Patent Document 3: Pamphlet of International Laid-Open WO 99/31045    Patent Document 4: Pamphlet of International Laid-Open WO 99/52856    Patent Document 5: Pamphlet of International Laid-Open WO 00/02846    Non-Patent Document 1: Drugs of the Future, 1993, volume 18, no. 6, page 542    Non-Patent Document 2: The American Society for Pharmacology and Experimental Therapeutics, 1993, volume 44, page 1100